Polishing machine



March 16, 1937. o. DOUTT POLISHING MACHINE 5 Sheets-Sheet 1 Filed NOV.14, 1932 ZZ El March 16, 1937. O DOUTT 2,073,785

POLISHING MACHINE Filed Nov. 14, 1932 5 Sheets-Sheet 2 Z E YEIF 022/672Dog/z.

March 16, 1937. o, DC JUTT POLISHING MACHINE Filed Nov. 14, 1932 5Sheets-Sheet 5 Owe would Mar ch 16, 1937. DOUTT 2,073,786

POLISHING MACHINE Filed Nov. 14, 1932' 5 Sheets-Sheet 4 lllllllllll 9%ZL J v IIIIIJIWI ,0 8X E- (9. 81

Ola/6% Dow/t March 16, 1937. DOUTT 2,073,786

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Patented Mar. 16, 1937 UNITED STATES PATENT OFFICE POLISHING MACHINE.0wen Doutt, Detroit, Mich, assignor toGeneral Spring BumperCorporation, Detroit, Mich.,a corporation of Michigan ApplicationNovember 14, 1932, Serial No.'642,478 '7 Claims. (Cl. 51-38) Tlhldinvention has to do with machines for which it is possible for the wheelto move axially polishing or. grmding work such as bumper bars while itis rotating and thereby follow the irregand has for one of its essentialobjects to provide ularities and offset edgesin the bar which is being ra machine of this character for grinding bumper ground.

bars of irregular or offset contour. Another object of theinventionresides in the In 'the course of rolling, bending and heat provision ofa machine of this character includt eatment to which bumper bars aresubjected ing means for positioning a plurality-of polishing preliminaryto the grinding and polishing. operwheels at different heights and indifferent planes 1 atlons, at least one edge of practically every bar inoperative relation to the bars to be polished,

0 becomes somewhat .uneven. In grinding bars for simultaneous engagementwith the bar. which have plane impact surfaces, and whose A furtherobject of the invention resides in the edges do not includesubstantially offset or bent provision of .a polishing machine forbumper portions, no diihculty is ordinarily'encountered bars embodyingmeans cooperating with the bar r since the grinding wheel used ingrinding such forproperly positioning a plurality of polishing 10 barshas a grinding face of such width that the wheelsin simultaneousoperative relation to the i5 entire "surface to be ground lies betweenthe bar. planes ofthe sides of the wheel. Where, how- Another object ofthe invention resides in the "ever,the impact surface of the bar istransverseprovision of a polishing machine including means ly crownedcrctherwise non-rectilinear, and its for affording the positioning of apolishing wheel edge or edges are irregular, considerable difiiculatdifferent elevations and in different planes 20 ty arises since therigid mounting. of the grindaccording as'the surface of the bar to beground ing wheel makes it impossible for the wheel, or polished isvertically inclined and includes whose grinding face in such case iscorrespondlaterally offset portions. mgly' transversely shaped, tofollow the irreg- It is still a further object of the invention to Vular1ty even.though the latter is very slight. provide a machine of thischaracter which em- 5 Oftentlmes heretofore when three or more wheelsbodies acarrier for the Work to be pol sh d, the operated"simultaneously on a bar such as one carrier being provided'with meanscooperating with edge irregularities and transversely crowned,with'means movable with the polishing Wheel for for example, even wherethe bar was mounted prop r y positioning h Wheel at different for slightlateral play, some portions of the vations and in different planes inaccordance with 30 crowned or like surface and of the edges of the thelocation of the surface to be ground or bar were ground less thanothers, and some not polished. at all, and a defective bar was produced.Another object of the invention consists in Numerous bumper designs invogue .at present the provision of a polishing wheel and a prime requireflat and crowned or other non-rectilinear mover therefor, t e t being soconnected that 35 bars, portions of which are substantially offset orthe po is Wheel iS capable of being Positioned .bent edgewise. In thecase of flat bars the grindat different distances from the prime moverwhile ing could be effected by employing wheels of sufthe polishingwheel is being driven therefrom.

1 ficient width. but their initial cost and upkeep Another object of theinvention involves the would be prohibitive. With a crowned orlikeprovision of a'flexible coupling between a polish- 40 surface, as wehave seen, grinding of the offset ing wheel and its prime mOVBI, d meansi portions with grinding machines heretofore in dependent-of these partsfor automatically caususe cannot be effected. The edgewise offset -por-'ing the wheel to be positioned .at different distions of the flat andcrowned surfaces to be tances from .the p e-m v r h le the same isground have heretofore been ground by hand being driven thereby. 5 inconjunction with agrinding wheel. This has It is also -.an object .oftheinvention to proinvolved great expense in the manufacture of vide in aflexible coupling between a polishing each bar. wheel and its primemover, instrumentalities for Itis accordingly an essential object of theinyieldably holding the:polishing wheel in its outervention toprovidemeans by which it is possible most position relative to the prime mover.50 for the grinding wheel to follow the irregularities Inaccordance withthegeneral features of one and offset edges of a piece of work such .asa form of the invention, there is provided a conbumperbar. veyorprovided with resilient supports for the It is another object of this.invention to provide endsof a bumper bar whereby the. surface to be afloating mounting for a grinding wheel by polished is positioneduppermost. 'A template is arranged to travel with the conveyor and isprovided with one or more laterally offset portions according as thepart to be ground is provided with laterally offset or displacedportions. A polishing machine frame is provided in cooperative relationto the conveyor and carries for vertical displacement therealong aplurality of motor-polishing wheel units, one or more of which may bearranged for cooperation with the same template. A flexible couplingbetween each motor and its cooperating polishing wheel affords relativeaxial movement therebetween, and a follower arranged for movement withthe mounting for the polishing wheel is spring pressed toward and intoengagement with the template so that the latter moves the polishingwheel into different planes in accordance with the lateral offset of thediiferent portions of the bar.

In another form, the wheel is mounted to float freely in both directionsaxially between limits determined by the maximum lateral extent of thetransversely crowned or other impact surface of a bar whose edges arenot substantially offset but at least one of whose edges is irregular.

With this construction, it is possible to maintain the polishing wheelin operative relation to the entire surface of the bar to be ground without the need of manual and time-wasting effort for shifting either thepolishing wheel into a diiferent plane for engagement withcorrespondingly oifset portions of the bar, or shifting the bar toposition an offset portion of a surface thereof into a position to beground by the polishing wheel. This shifting of the polishing wheel isautomatic and requires no attention whatever, and this construction maybe built at a low cost of manufacture.

Further objects and advantages of the invention will appear as thedescription proceeds.

This invention (in preferred forms) is illustrated in the drawings andhereinafter more fully described.

On the drawings:

Figure 1 is a fragmentary front view of a polishing machine constructedin accordance with the principles of the present invention.

Figure 2 is an end view of the structure shown in Figure 1, looking fromthe right, certain portions including the conveyor belt being shown insection.

Figure 3 is a longitudinal sectional View taken approximately in theplanes indicated by the line III-III in Figure 1, certain parts beingshown fragmentarily.

Figure 4 is a sectional view taken approximately in the plane indicatedby the line IV-IV in Figure 3.

Figure 5 is a sectional view taken substantially in the plane indicatedby the line VV in Figure 3, showing a portion of the conveyor belt.

Figure 6 is a longitudinal sectional view taken substantially asindicated by the line VI-VI in Figure 2, showing a flexible shaftcoupling, the shafts being illustrated fragmentarily.

Figure 7 is a sectional View taken substantially in the plane designatedby the line VII-VII in Figure 2.

Figure 8 is a fragmentary elevation of a modified floating grindingwheel mounting.

Referring now more particularly to the drawings, the machine comprises aframe work including a plurality of stanchions l arranged in tandembeside a conveyor belt 2 which is preferably endless and travels overpulleys 3 having a suitable source of power (not shown). A table orapron 4 is secured to the stanchions and extends substantiallythroughout the length of the machine for supporting the portion of thebelt which is uppermost as shown in Figure 2. Each stanchion l carries amotor-polishing wheel unit 5 including a motor 6 having a driving shaft7 and a grinding wheel 8 having a driven shaft 9, the two shafts beingconnected through a flexible coupling If] for relative axial movementWithout disturbing the driving relationship therebetween. Each of theseunits is carried by a support i l including the rods l2 and 13 which areslidable vertically in bearings carried stationarily by the stanchion ormain frame, the rod l2 having upper and lower bearings M and i5 and therod :3 having the lower bearing IS.

The slide rod l2 projects upwardly through the bearing l4 and carries atits upper end a sleeve I! provided with an arm l8 which is tapped toreceive a threaded adjusting member l9. The member I9 is engageable atits lower end with the top of the stanchion l to limit the downwardmovement of the motor-grinding wheel unit support I I, and obviously themem ber 19 may be adjusted to vary the extent of vertical movementthereof.

The support H is secured to the rod l2 at its lower end by means of asleeve 20 which is counterbored at 2| to receive the upper end of thebearing sleeve I 5, and bracket means 22 associated with the grindingwheel head 23 is secured to the intermediate portion of the rod' 12 bybolts. The support H is provided with a second sleeve ing sleeve IS inexactly the way in which the previously described sleeve 20 cooperateswith the bearing sleeve l5, and is of substantially the sameconstruction. The support H is further provided with an upper sleeve 24which is suitably secured to the upper end of the rod l3. The grindingwheel head 23 includes axially stationary and relatively movable parts,and it is the axially stationary part 41 which is secured through thebracket means 22 to the rod l2.

In order that the pressure which is exerted by the grinding wheel 8 uponthe bar to be ground due to the weight of the motor-grinding wheel unitand its support ll may not be excessive, the latter are counterbalanced.To this end, a bracket 25 is secured to the stanchion I and pivotallycarries a bar 25 intermediate the ends of the latter. One end 27 of thebar 25 has a loose pivotal connection with an adjustable rod 28depending from the support H, and on the other part of the arm 26 areprovided stationary and adjustable counter weights 29 and 30,respectively, whereby the weight of the unit If and the parts carriedthereby is largely overcome. It has been found advantageous to socounterbalance the parts as to provide a pressure of approximately 15pounds of the grinding wheel 8 upon the bar to be ground, but it isobvious that the pressure may be varied as desired.

The bar to be ground may be supported in any suitable fashion, themethod herein disclosed being presented for illustrative purposes only.As here shown, yieldable brackets 31 are spaced apart in accordance withthe length of the bar to be ground and are secured through anintermediate plate 32 to the conveyor 2 in position to receive the endsof the bar to which said brackets are temporarily secured as at 33. Theends of the bumper bar are here shown as rounded,

20 which cooperates with the bear- 5 and cooperating portions of thebrackets 3i cor- 75 respondingly shaped, but it will be understood thatthis is for illustrative purposes only since the inventionhereinaftenmore fully described may be practiced regardless ofthe formwhich the ends of the bar andthe' corresponding portions of the bracketssupporting the same may take. While the brackets '3l may be rigid, theyare preferably made of leaf springs or otherwise constructed to provideresilient supports for the ends of the bumper bar.

The flexible coupling is providing forrelative axial movement betweenthe motor shaft 1 and grinding wheel head shaft 9 is shown in detail inFigures 6 and 7. This structure comprises a tube 34 provided at one 'endwith a liner 35 which is securely held therein by any suitable meanssuch as'dowels 38. The liner 35 is keyed at 31 tothe motor shaft i sothat there can be no relative axial movement between the tube 34 and.the shaft 1. The remainder of the tube 34 is provided with a pluralityofpreferably equally spaced longitudinal internal grooves '38 constitutingouter races for a corresponding number of series of bearing balls 39.The tube 34 slidably accommodates a bearing sleeve 48 provided with aplurality of longitudinal externalgrooves 4| for registering with thegrooves 38. The grooves 4| provide inner races for the balls 39. Endcaps in the form of ring-like members 42 are formed with externalcontours corresponding with the internal contour of the tube 34 andthereby provide end closures for the cylindrical spaces provided by eachpair of registering grooves 38 and 4|. The end caps 42 are securelyfastened tothe ends of the sleeve by screws 43 or the like. The balls 39are separated from each other by suitable rings 43a arranged for aslidable lit in the registering grooves 38 and 4|. There is therebyestablished a substantially frictionless spline-connection between thetube 34 and the sleeve 48 and associated parts. 7

A ring shaped end cap 44 is securely fastened to that end of the tube 34opposite the liner'35 by screws or any other suitable means (not shown).The caps 42, the sleeve 49, and the liner 35 are bored centrally at 45to substantially the same diameter to receive the respective shafts 9and 1, the grinding wheel shaft 9 being keyed at 46 to the bearingsleeve 49. Thus regardless of the position of the shaft 9 relative tothe shaft 1 therewill at all times be a driving relation therebetween.

The grinding wheel head is designated generally by the numeral 23 and issupported by a sleeve 47 which carries the bracket 22 by means of whichthe same is mounted on and supported by the slide rod I2. A tubularmember 48 is mounted for rotation relative to the grinding head shaft 9by means of bearings 49 and 54 which are spaced apart on the shaft 9 bymeans of a sleeve 5|. The ends of the tube 48 are counterbored foraccommodating the bearing structures, thereby providing shoulders 52 and53. An oil shield 54 is positioned in engagement with the shoulder 52 onone side and a face of the outer race of the bearing 49 on the otherside, the opposite face of the bearing 49 at the inner race engaging acollar 55 on the shaft 9, thereby positioning the bearing 49. A bearingretaining ring 56 is arranged outwardly of the bearing 49 and isprovided with an outwardly extending flange 51 which engages theadjacent end 58 of the tube 48 and extends therebeyond. A-dust guard 59is secured at 68 to the flange 51 and extends substantiallycylindrically in coaxial relationto the: shaft 9 and sleeve 48.

i The bearing is received in a bearing holder 8| which fits in the othercounterbore of the sleeve with a press fit. and engages the shoulder 53.The shaft 9' isthreaded at 62 to receive a bearing. retainer nut 63 bywhich the bearing 58 is heldin engagement with theisleevetl. The

jouter race of the bearing 50 is properly positioned and .held in placeby virtue of the cooperation betweenthe bearing retaining ring 64 andthe bearing holder (it, the two parts being secured together as shown at85. The sleeve 48 is thus journalled about the shaft 9 but is heldagainst axial movement relative to the shaft 9.

The tube 48 is provided with a. plurality of preferably equally spacedlongitudinal substantially' V-shaped ball races 86 which cooperate withregistering. grooves 61 'in the supporting sleeve 41 to receiveanti-friction balls 68 and thereby establish a sliding connection. The

mounting sleeve 41 is provided with an individ- To insure against escapeof the anti-friction balls 68, ball retaining rings H and 12 are securedto the ends of the mounting sleeve 41 in any suitable manner as byscrews Na and 52a. The rings H and 12 are provided with internal gaskets13 which engage the outer cylindrical surface of the tube 48. Theportions of the mounting sleeve 41 provided with the grooves 6! aresomewhat enlarged radially to accommodate the said grooves, and therings H and H are correspondingly shaped.

The ring. H and mounting sleeve 4l are'provided with registering slots14 and 15, respectively. in which the offset arm 16 of a bracket Tl isslidable. The arm i5 is secured as by one or more screws 18 to the tube48 and moves therewith, and serves as an additional means whereby thetube 48 and the parts secured there to are splined throughout part ofthe movement with respect to the mounting sleeve 471.

a The mounting sleeve 4'! is provided at a point remote from the bracketl! with a depending lug l9, and the lug l9 and bracket T! are yieldablyurgedaway from each other by a spring 80 disposed therebetween andsurrounding telescopic elements 8| and 82, removably secured to theparts TI and l9.

The lug 79 has also removably secured thereto a rod 83 extending towardthe bracket 11, and the bracket TI has removably secured thereto a guidemember 84 which extends toward the lug 7 l9 and is provided with a hole85 through which the rod 83 extends. Stop means such as lock nuts 88 areapplied at a desired location along the rod 83 for engagement with theportion 81 of the guide member 84 which is telescoped about the rod 83,to limit the movement of the bracket 11 away from the lug '59 under theinfluence of the spring 80.

The'bracket TI is provided adjacent its lower end with a slot 88 throughwhich the threaded shank 89 of a clevis 90 is adjustably received. Theshank 89 is flattened on opposite sides as shown at 9! to fit in theslot 88 so that the shank 89 is slidable but not rotatable therein.Adjusting nuts 92 applied to the shank 89 on opposite sides of thebracket 11 serve to adjust the clevis 90 both vertically andhorizontally respecting the bracket 11.

The clevis 90 carries a roller93 which operates as a follower inconjunction with a cam to be hereinafter fully described.

Referring now more particularly to Figures 1 and 5, brackets 94 and 95for a cam indicated gen- 15 erally at 96 and consisting for illustrativepurposes only of two parts 91 having edges 98 are secured to theconveyor 2 between the supporting elements SI for the bar A to bepolished or ground. The cam 96 is formed preferably from another bumperbar and consists of that portion of the bumper bar which includes theoffset edges, and is retained in the flattened or uni-planar conditionas shown in Figure 1. Where the length of the cam will permit, it may bemade in one piece; otherwise, it is made in two or more pieces as shownin order that the conveyor 2 may traverse the pulleys upon which it ismounted, without difficulty. The width of the cam 96 is immaterial, butit is necessary that at least one of its edges, preferably the edge 98adjacent the roller or follower 93, conform exactly to the correspondingedge of the bar A to be ground, and this will of course be the casesince the cam is made from a bar which is identical with the bar A. Theparts 9'! of the cam are sufficiently close together as shown at 99 toestablish substantial continuity of the edge 98.

Preferably two brackets 94 and 95 are employed for supporting each campart 91, although 40 it will be understood that one or any other numberof supports for each part 91 may be provided so long as the same isproperly positioned to perform the intended function. Plates I89 aredisposed between the belt 2 and brackets 94 and 95, 45 and are securedto the belt 2 as at IUI. The brackets 94 and 95 are mounted on theplates I00 by pin and slot connections I82 so that the same may beadjusted to thereby adjust the cam 98 laterally.

It will be observed that the follower 93 is arranged so that when theguide member arm 81 abuts the stop means 86, the follower contacts theedge 98 where the latter is not offset as at I03. Assuming that the belt2 moves as indicated by 55 the arrows B, the bar A will be engaged bythe grinding wheel 8 substantially at D since the adjustable stop [9 isarranged to prevent the wheel 8 occupying a lower position. The follower93 at that time will be positioned at a point spaced from 60 the forwardend I04 of the cam 98, the wheel 8 being positioned in proper grindingrelation to the bar A by the spring 80 and the engagement of the stopinstrumentalities 86 and 87. The wheel 8 is maintained in the same planeby the same instrumentalities throughout that portion of the bar A whichis straight, i. -e., until the point E in the bar A is reached where theedge of the bar begins to deviate or bend. At this point, the follower93 of that particular wheel is positioned as shown at the left in Figure1, in substantial engagement with the extreme forward portion I93 of thecam edge 99. During the movement of the wheel 8 from the position D to75 the position E, the wheel is raised by a cam action afforded by thefact that the bar A between these two points is bowed.

As the bar A continues forward, the follower 93 is shifted laterally bythe offset cam edge 98 causing the wheel 8 to shift exactly inaccordance with the shape of the bar A from the point E to the point Fwhich for illustrative purposes is shown as located, at the center ofthe bar A and at which point the maximum amount of shift of the wheel 8has been effected by the cam 96. It will be observed that the roller 93is of such length and is so adjusted in the slot 88 of the bracket 11 asto compensate for the bow in the bar A throughout the portion of the barwhich is offset, namely from the point E to substantially the point F inthe upward movement of the wheel 8, and from F to G corresponding to thepoint E but on the down side of the bar A. This accounts for the showingin Figure 1, wherein the roller 93 at the left is shown engaging the cam95 at approximately half the height of the roller, and the roller in themiddle of the figure engaging the cam 96 adjacent the lower end of theroller. Obviously the stop means 86 may be positioned elsewhere alongthe rod 83 according to the extent to which the edges of the bar to beground are offset, and the clevis 98 may be adjusted vertically of thebracket H, and the size of the clevis and roller carried therebycorrespondingly varied for bumpers which are more or less bowed.

By reason of the fact that the grinding wheel head is floatinglysupported, the grinding wheel, which conforms transversely to thetransverse contour of the surface to be ground (in this instance thesurface to be ground is convex) is enabled to be shifted by the bumperbar itself in accordance with the slight unevenness of its edgesresulting from the various treatments to which the bar is subjected inthe formation of the same as a bumper bar Thus the entire surface of thebar to be ground will be polished with an even smooth finish, withouthigh spots or dull spots.

To the end that any bumper bar having a surface to be ground which isother than straight, transversely, such as a transversely convex barherein illustrated, but whose edges are not offset, may be given auniform finish, the telescoping parts BI and 82, the cooperating spring80, the clevis 90, roller 93, cam 96, and associated instrumentalitiesmay be dispensed with. As explained in a previous paragraph, the shapeof the bar and grinding wheel, transversely, is such as to cause thewheel to follow all inaccuracies in the edges of the bar, therebyaifording a smooth finish for the surface to be ground. In such event,the stop instrumentalities comprising the guide element 84 and'rod 83are retained and a second stop means 86a employed in conjunction withthe stop means 86. The two stop means 86 and 88a are preferably spacedapart sufficiently to allow the guide arm 8! to have a traveltherebetween to an extent somewhat in excess of the width of the bar tobe ground, so that the grinding wheel 8 may travel suificientlylaterally of the bar in accordance with the irregularity in the edgesthereof. Such irregularities as may exist in the edges of the bar willbe slight and the grinding Wheel will float between the two stop means86 and 86a, so that the wheel will readily pass into proper positiononto the following bar without the need of any special positioningmeans. It will thus be apparent that by establishing what amountssubstantially to a tongue and groove relationship between the bumper barand. the polishing "wheel, 'as by employing a grooved wheel whengrinding a flat or crowned bar, or "a transversely convex'surfaced wheelfor a transversely concave bar, a uniformly polished surface on thebar'will be obtained in spite of edge irregularities therein. Inaddition this relationship makes itpossible for the wheel, by reason ofits ility tomove freely in an axial direction, to shif n" accordancewith the offset in the bar, the bar itself in such cases serving as themeans for shifting the wheel and holding the same in proper position forpolishing. With the bar having one or more edge offset portions and thisrelationship established, the stop means 86a may be removed and a springmeans such as that described above employed for urging the grindingwheel head outwardly. Such a spring need only be of sufficient strengthto overcome whatever resistance is offered by the ball spline connectionand would not be suflicient to cause the wheel to grind one portion of atransversely non-recti== linear bar more than another portion thereof.The spring would, however, position the grinding wheel so that uponleaving one bar it Would be correctly positioned to readily engage theproper portion of the surface of the succeeding bar to be ground.

It will be seen from the foregoing that in accordance with the presentinvention there is provided means for grinding a longitudinally fiat orbowed bar in such a manner that the surface operated upon will have auniform finish, regardless of edge irregularities or offsets in the barand regardless whether the surface to be ground is transverselyrectilinear or non-rectilinear.

t will be noted that clamp flanges I are applied on the shaft 9 onopposite sides of the grinding wheel 8 for holding the same in properoperative position. If desired, shims or washers may be employed inconjunction with these flanges for the purpose of adjusting the wheel 8along the shaft 9.

I am aware that many changes may be made and numerous details ofconstruction may be varied through a wide range without departing fromthe principles of this invention, and I, therefore do not purposelimiting the patent granted hereon otherwise than necessitated by theprior art.

I claim as my invention:

1. In a machine for polishing a longitudinal substantially sinuoussurface of a bumper bar, a support for holding such a bar in a positionto be engaged by a polishing wheel, a polishing wheel having a polishingsurface of a width sub stantially equal to the maximum dimension of thebar surface at right angles to the plane of rotation of the wheel, meansfor driving the wheel rotatably, means for causing relative movementbetween the support and the wheel in a direction parallel to the planeof the wheel, means for causing the wheel to automatically shift axiallyrelative to the bar as the wheel passes along the diagonal part of thebar tothereby polish the sinuous surface of the bar, and means providinga support for the wheel so that the same may float up and down in aplane of its axis, to enable the wheel to polish vertically offsetportions of the surface of the bar.

2. In a machine for polishing edge-offset bars, a movable support forsuch a bar, a template movable with the support and having an edgeparallel to an offset edge of the bar, a plurality of polishing wheels,means supporting the wheels for axial movem'ent and a follower for saidtemplate and" movable with each of said wheels; wherebys'aid wheels willsimultaneously polish relatively offset portions as well as relativelyalined portions of the bar during continued movement of the latter. r I3.' In a machine for polishing edge-offset bars, a movable support 'forsuch a bar, a template movable with the supportand having an edgeparallel to an offset edge of the bar, .a plurality of polishing wheels,means supporting the wheels for axial movement, and a follower for saidtemplate and movable with each of said wheels, whereby said wheels willsimultaneously polish relatively offset portions as well as relativelyalined portions of the bar during continued movement of the latter, andmeans for yieldably holding the followers in engagement with thetemplate.

4. In a machine for polishing edge-offset bars, a movable support forsuch a bar, a template movable with the support and having an edgeparallel to an offset edge of the bar, a plurality of polishing wheels,means supporting the wheels for axial movement, and a follower for saidtemplate and movable with each of said wheels, whereby said wheels willsimultaneously polish relatively offset portions as well as relativelyalined portions of the bar during continued movement of the latter, andmeans for limiting axial movement of the wheels so that the followersare in position to engage the suceeding templates for enabling thewheels to polish succeeding bars.

5. A polishing machine including a rotary polishing member for polishinga bar, said bar having portions relatively offset transversely withrespect to a plane of rotation of said member, and means for conveyingthe bar relative to said member in the general direction of the lengthof the bar, said member being supported for movement transverse to saidplane and being formed to have a cam and follower relation with the barso that said member will be shifted transversely of said plane by thebar as the bar is conveyed, and means for holding the polishing surfaceand the surface to be polished interengaged under pressure during thepolishing operation.

6. A polishing machine including a polishing member for polishing aplurality of bars each having a portion relatively offset transverselywith respect to a plane of rotation of said member, and means forconveying said bars relative to said member in the general direction ofthe length of the bars, said polishing member being supported formovement transverse to said plane and being formed to have a cam andfollower relation with each bar so that said member will be shiftedtransversely byeach bar as the bar is conveyed, means for holding thepolishing surface and the surface to be polished interengaged underpressure during the polishing operation, and means for supporting thebars in a longitudinal series with the rear end of each aligned intandem with the front end of the succeeding bar, whereby upon becomingseparated from the rear end of one polished surface said member becomesengaged with the front end of the succeeding surface to be polished,without adjustment.

'7. In a machine for polishing bars such as bumper bars, a plurality ofrotary polishing wheels, means for supporting the bars longitudh nallysubstantially parallel to the wheels, means for moving the support in adirection parallel to said wheels, means mounting each of the wheels forindependent and combined axial and cross-axial movement in addition toits rotation, so that the same polishing area thereof may polishselectively a straight bar, a bar having an edge offset in a planeparallel to the Wheel axis, a bar whose edges are offset in a plane atright angles to the wheel axis, and a bar having portions of its edgesofiset in neither of said planes, said wheels being spacedlongitudinally to such an extent as to be engageable with spacedportions of the same bar, and means for holding the wheels in polishingengagement with such spaced portions of a bar, regardless whether suchportions are relatively offset.

OWEN DOU'I'I.

